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Location: Essex UK
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The 3.2 SS Carb dilema
Ok guys thoughts...
Recently a 3.0 engine which was modified to a 3.2SS sold.It was from a respected 911 performance company. Bear in mind,this was a UK car,with Larger ports. It was a standard "text book" build with 964 cams,high comp pistons.Weber IDA3C carbs. This engine dyno at 230ft lbs torque.260BHP. Thats very good numbers,for a low cost 3.2SS build Heres the kicker.These were custom carbs.Original 40mm bore to 44mm. The usual fitment or bore would have been 46mm. However the guys who did the build speced only 44mm. Perhaps the increased velocity,of the slightly smaller bores, helped to get this build to a very healthy 260hp? Thoughts.... |
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The TQ number is the healthy high number , at what rpm for the tq and hp
The weber conversion is a normal conversion, what size chokes ? Ian
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Kermit, 73 RS clone, Just Part of the Team Chris Leydon ,Louis Baldwin ,Peter Brock ,Riche Clark Jerry Sherman ,Rob McGlade ,Donnie Deal Hank Clarkson ,Craig Waldner ,Don Kean ,Leroy Axel Gains Last edited by icarp; 10-03-2022 at 03:04 PM.. |
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Sounds like with 964 cams, the builder was looking for more lower rpm torque rather than higher rpm HP. Looks like he succeeded. The lower rpm engine will benefit from smaller bore carbs, ensuring a greater vacuum, or lower pressure, at the jets. An S or mod S cam would pair better with 46 bore.
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Is this measured at the flywheel on and engine dyno or WHP on a "rolling road dyno"?
Cheers
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Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 |
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Wow very strong numbers that’s impressive. It would be interesting to put the car on a chassis dyno just to see how much power is actually lost. I know 15-20% is the common thought
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it's not leaking....it's just marking it's territory |
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Seems like an ambitious dyno machine was used to produce those numbers… look forward to hearing what you find out.
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It's a 914 ...
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I'd guess you wouldn't notice much difference between 44 mm and 46 mm carbs.
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Thanks for reply guys.Its interesting.Unfortunately,no more details are known at this time.Ill try and dig a bit further.
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Quote:
Every UK dyno I have seen numbers from over the last 35 years is ambitious. That said, the peak "number" is not important, the change from stock or known baseline data is what is important. Cheers
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Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 |
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Quote:
I looked at post on DDK again.The builders were selling 5/6 engines.Plus its a few years old.I stumbled on it by chance,whilst perusing ads.That said Tech 9 the builder/seller have a good name. Of course Dyno numbers arent always what they seem,and I respect your input greatly. My original point,was concerning the boring of the carbs,and as to whether the slightly smaller bore could increase velocity,and combustion? I have noticed a disparity between carb size used in UK and USA. Whereas a USA builder,will tend to use 46mm (pmo for instance) Over here many use 40mm.Not saying anyone is right or wrong.Just different. |
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Please correct me if this is bad form.
I can't comment on your modified carbs but some of the info here applies to my current project. I have a 3.2 SS and want to use the practically new 40s that I already own. I have a great selection of jets, ACs,emulsions etc. and 34 and 36 vents I hope to get info on a known combination as a good starting point. I'm encouraged knowing that these carbs are used successfully in Europe Engine specs.... large ports, DC60, S spec dizzy, Mahle 98mm PCs 9.8 to 1 TIA Rory |
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Quote:
Peak dyno numbers are not important, it is a tool to tune with. If you are happy with the performance, that is ALL that matters. Cheers
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Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 |
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